All of Britain's leading manufacturing companies now have at least one female director on their boards, a new study has shown.

However the sector is being urged to ditch its unglamorous image and develop more talent from "classroom to boardroom".

Manufacturers' organisation EEF said women now make up 21% of FTSE 100 directorships in the sector.

Women hold 64 out of 305 manufacturing board seats, it said, up 8.4% on the figure a year ago.

EEF said more than a third of the firms already have exceeded Lord Davies' Women on Boards report, which called for 25% representation.

It said GlaxoSmithKline and Unilever both have five female board members, while drinks firm Diageo has four.

Diageo leads in percentage terms as 44% of board places are taken by women.

It added that two manufacturers noted in last year's inaugural study did not have any female representation - Croda International and Melrose Industries - now do, however both have since dropped out of the blue chip FTSE index.

The trade body said the percentage of non-executive roles now taken by women has grown 2% to 25% in the last year, but executive roles have stayed still at 8%.

Less than one-tenth of female board members are in executive roles compared to 29% of their male peers.

EEF chief executive Terry Scuoler said: "The message from this report is clear - manufacturers are heading in the right direction, but cannot afford to let up.

"We are matching other industries for female board representation, but there is no room for complacency.

"If our sector is to continue to thrive we need to be fishing from the entire talent pool and that means ensuring women have the right skills and opportunities and are represented at every level."

He added: "Many of the leading women in manufacturing are equally clear - quotas are not the answer.

"They advocate evolution, not revolution, with companies continuing and improving their work to identify and nurture talented women and taking bigger strides in showing that a career in our sector is an attractive, exciting and equal opportunity for all.

"But, this isn’t just about what we as manufacturers can do. The work starts in the classroom where we must see a boost in the number of young women taking STEM (science, technology, engineering and maths) subjects and encouraged to raise their career expectations."

The study, undertaken in conjunction with Lloyds Bank Commercial Banking, has also seen the high street lender make a promise for its own career improvement for female staff.

Its UK head of manufacturing, David Atkinson, said the bank intends to have 40% of senior roles held by women by 2020.